The compound (1R,2R,3S,5S)-2-methoxymethyl-3-(3,4-dichlorophenyl)-8-azabicyclo[3.2.1]octane is disclosed in WO 97/30997 (NeuroSearch A/S). Therein, the citrate salt was prepared (Example 15).
For commercial use, however, it is important to have a physiologically acceptable salt with an optimal combination of stability, solubility, non-hygroscopicity, bioavailablity and good handling properties, such as a well defined melting point and a reproducible crystalline form.